Astronomy and Cosmology

Hi there. I'm writing a sci-fi story for a video game. At some point in time an advanced civilization from the future, say 4010, creates a wormhole for a not so advanced civilization spacecraft in the past, say 2050, to travel through. The idea is for the not so advanced civilization spacecraft to meet the advanced one in its own time, 4010. The question is (theoretically and sci-fi speaking): how many years would have passed for the advanced civilization in 4010 until the not so advanced civilization spacecraft arrived? Its possible that I'm missing some pseudo-scientific data so feel free to complement my reasoning. I hope I made it clear. …

i heard about the phenomenon of rogue black holes which can get ejected when two galaxies collide in certain circumstances these black holes might carry no stars or planets with them and would therefore be invisible, i guess which gave me a frightening thought if one were hurtling through the abyss directly towards us, possibly about to enter our galaxy near where earth is located would we know in advance?

in terms of looking out of the milky way to the other galaxies in the outer universe how much of it can we see from our location in the milky way? for exmaple, imagining the milky way disc was a clock if we are at 6 o clock now ,in the milky way, that if we were at 7 o clock, or 3 o clock we would see a whole different selection of galaxies? or can we already see the full 360 degrees of the observable universe from where we are using the instruments we have? unless you guessed, im no scientist, so go easy please LOL

I know it sounds like freaky, but I haven't found such evidence. I know that Galileo proved the possibility that when the earth moves as an inertial system, this movement may be imperceptible, but the possibility is not proof that this is the case. Similarly, with the reasoning of Copernicus and so on. Meanwhile, the ancient concepts of spheres are very close to what is actually observed, for example, distant stars are almost motionless, and so on. And besides, if we (purely hypothetically) admit the existence of the ether, then the immobility of the earth explains the absence of the etheric wind By the way, were there any attempts to detect the etheric wind…

Normal matter clumps under the influence of gravity, but this is only because of other interactions: normal matter particles collide, loose energy and so get closer to each other. And because of the conservation of angular momentum, structures made of normal matter tend to concentrate in more or less disk-like structures (planetary systems, galaxies). Now we learn that most galaxies are supposed to be embedded in a sphere of dark matter. These are spheres, not disks, because dark matter particles, interacting through gravity only, cannot average out their angular momentum, and so do not form a disk-like structure. So far so good. But if we suppose that dark matt…

I'd like, if I may, to pick up on one issue.. MigL citing a previous post from Joigus, makes this statement: "The gravity produced by a BH is no different from any other equivalent mass". Now, I wonder whether this takes into account, the Black Hole's extremely small physical dimensions. Wouldn't these small dimensions cause a drastic reduction in the BH's ability to exert gravity. Following the diminishing inverse-square law from its outer surface?

Are there any connections between the Black Hole model and this model (is it a model?) of Penrose? Would the latter model imply that there was no singularity at the centre of a BH? Some mechanism whereby all the surrounding forces ,Leonidas- or Dutch- boy- with- finger- in- the -hole of -a -dyke like were held at bay in the smallest of confines.

Hello gentlemen! I recently discovered Sir Roger Penrose's conjecture about Conformal Cyclic Cosmology, and I find it very interesting. His claim that there are visible traces of the past aeon (former universe) in the CMB is a very intriguing, but I just can't wrap my head around how a cold, massless, radiation filled universe can turn into a hot dense singularity. Maybe someone here can explain it in layman's terms? What do you think about the CCC theory? Here's a 39 minute video where he explains it. But the step from old to new universe just doesn't click with me.

I can imagine tuning to a channel on tv or youtube live streaming our solar system. There could be multiple satellites working in tandem with each other and each is spread over or positioned at a specific location, presumably around the solar system. That could enable us to switch a specific camera to another.. to get a different view of the solar system, just like in a hockey game. In a hockey game, a couple of cameras are positioned at certain location around the hockey rink. The broadcasting camera changes to another one as depend on a live game. So the satellites could act similar to the broadcasting cameras in the hockey, but with our solar system.

Hi, See: https://constantecosmologique.fr/ available in English What is your opinion please?

If microbial life is discovered in Venus' atmosphere, and samples are collected, will science be able to tell us whether its ancestry somehow found its way there from Earth, or whether it's definitely a product of abiogenesis on Venus? Thanks GIAN 🙂

Apparently the Orion Project for nuclear powered spaceflight asserted that by this method with an acceleration of 1G an Orion spaceship could attain a speed of 10% of the speed of light (c.) Mathematically, how do I work out 1. the length of time it would take to get from 0 to a speed of c/10 (ship's time,) and 2. what would be the distance travelled in that time? Cheerz GIAN🙂

Do I understand that right: In next video it says: The mass of planet Earth divided by it's radius=it's gravity? Video link removed by moderator Video link removed by moderator

Earth has an atmosphere that prevents particles to reach Earth’s surface, and the Sun has an atmosphere that prevents particles from the universe to reach the Earth. Or not?

Terraforming planets will take a back seat to building spacecraft that can be "all the comforts of home." Why make the effort to terraform Mars when you could much easier build a giant spacecraft that can travel for decades without needing anything, except to stop occasionally at an asteroid to collect water-ice for water, air and fuel, and some useful minerals.

If we took two lines leaving a single point and then some where in far distance the outer sides of each would come together. Could this be how the universe is racing away because its pull itself into itself in the distance place?

Hi Just been watching a video on PBS space time (you tube channel) on black holes (well building modelsi a lab which is also interesting) this is really interesting with Hawking radiation being apparently responsible for black hole, mass loss . This got me thinking if white holes are the opposite to black holes as they emit energy rather than pull it in, and a white hole is possible at the other end of a black hole, are these also perhaps responsible for mass loss. I think the two being linked is some sort of theory or idea anyway, but would it need a model where we take a black hole and a corresponding white hole would emit mass = to that taken in by the bla…

Once you cross over the event horizon of a black hole you cross the point of no return. The speed of light is 186,000 MPS but once you cross over the event horizon you would have to have a speed faster than that to escape from the gravity of the black hole and nothing can move faster than 186,000 MPS because as weight increases with speed, once you reach that speed your weight becomes infinite so it would require infinite energy just to reach light speed. That is why you can't escape from a black hole since the escape speed is faster than the speed of light and you can't go faster than the speed of light according to conventional physics. Anyway, I was thinking, if …

This wasn’t my idea but Edward Snowdens which I heard on an episode of Startalk and it just struck me as a very compelling argument. He posited that an intelligent species would have a relatively small window of broadcasting radio signals in the clear before they started encrypting all their radio communications to be indistinguishable from background noise as a matter of course. Personally I can’t think of any reason why this couldn’t be true and it makes perfectly good sense. It also makes me think that it may already be happening but that’s besides the point. What do you guys think?

I am stumbled to see a young boy is able to present a simulation of how moon formed and how the trajectory formed by the moon. Nice theory by young man .Here is the link

Hello, I would like to share with you the info we have so far about habitable exomoons: 1. We have detected 9 exomoon candidates, but none of them are potentially habitable. 2. A habitable exomoon would have a mass between 0.25 and 2 Earth masses. 3. The mass of the host planet has to be at least 3 times the mass of Jupiter, and it should not be tidally locked to the star. 4. A study has identified more than 70 gas giant exoplanets that could host habitable exomoons, but all of them are located far away. 5. Within 100 light years, there could be around 33 habitable exomoons orbiting Sun-like stars, 109 around K-type stars, and 121 in red dwar…

Mars would appear to have many channels and alluvial fans that indicate that at one time it had water and maybe even seas but at the time this is thought to have taken place The Sun was significantly dimmer than it is today and unless Mars had a vast thick atmosphere this would seem unlikely. The Earth is thought to have frozen completely over at least twice in geological time so IMHO a balmy Mars with rivers and seas seems unlikely. On Earth large ice sheet often have lakes, streams, and rivers under them and we do see Moons that are ice covered but far enough from the sun that ice is stable. Mars is close enough to the Sun for ice not to be completely stable and s…

If we can create nuclear bombs 1000x hiroshima, wouldn't it be fairly simple to use it to power space ships which could accelerate to the point where a trip to the outer planets would take days rather than years? Is it true that this is already quite possible, but governments won't let us do it because of the potential dangers of nuclear accident? Cheerz GIAN xx

Hi all I would like to try and build a solar observer as detailed here https://www.space.com/15614-sun-observing-safety-tips-infographic.html Right now I have 2 pieces of card one is square with a pin hole in the center the other is just a piece of scrap a4 card.l The projector does work. I have got a basic pinhole projector working, is there a way to link distance from hole to the size of the projected image, ? Or the optimum size of hole and distance to where I am projecting to? Thank in advance for any help II can probably use a system lke this in a school or at the South Devon Tech Jam if we decide to actually do more than simply comput…

Just been reading the above article on Did a supernova trigger the late Devonian extinction? https://physicsworld.com/a/did-a-supernova-trigger-the-late-devonian-extinction/ Asf we think there was life on Mars a long time ago, would the rocks brought back from Mars by the newly launched Perseverance rover be tested for these radioactive isotopes too, to figure out if any radiation also reached the surface of Mars. So namely this seems to be: Samarium-146 Uranium-235 Plutonium-244 So some digging as to what protects us from Solar Flares What Protects the Earth From Harmful Solar Flares? Updated March 10, 2018 By Tammie…